The M4.3 system uses bigger photo sensors than the little Nikon which means the picture quality ought to be better.

Again, the OP is entertaining the GX1. Let's be objective here and as accurate as possible for his/her sake. The GX1 has better low light capability than the V1, but the V1 has more color depth and dynamic range than it or the Olympus EP-3.

The new sensors are of course better, which I stated in my first post.